1. Field of the Invention
The subject matter of the invention relates to a method and a test platform for developing a vehicle with several powered axles.
2. The Prior Art
Vehicle manufacturers today develop motor vehicles having one axle (typically the front axle) that is powered by a combustion engine and another axle (typically the rear axle) that is powered by one or several electric motors (for example, for single wheel drive systems), so-called hybrid vehicles. For the development of such a hybrid vehicle, the automobile must be equipped with both drive systems, which means the hybrid must be set up completely; however, this is an undertaking involving great complexity and expense, especially if any changes must be implemented on the test vehicle. In purely electrically powered vehicles it is possible to drive the front axle as well as the rear axle(s) independently by their own electric motors. An axle can also by powered by a single-wheel drive system.
In the development stage of motor vehicles it is necessary to create certain driving states in order to test how a vehicle behaves under certain conditions. This can be done on special test stands, for example roller dynamometers, or on test tracks (whether in the form of a real roadway or a special test terrain is not important in this context). Both options have advantages and disadvantages. Test stands do not necessarily allow for any type of duplication that may be desired because they are unable to simulate real ambient conditions with every degree of accuracy. Therefore, testing on a test stand can always only give indications as to the real behavior of the motor vehicle on the real roadway (even when the real conditions are approximated very closely). A test track, in contrast, is naturally limited in terms of its possibilities dependent on its course through different environments, routes, etc. Consequently, it is not possible to generate any unlimited number of desired driving states on a test track. Moreover, testing on a test track depends in most cases also on environmental conditions (temperature, moisture) and the test driver (clutching times, pedal position(s), steering angle, etc.) and is thus not completely reproducible. Nevertheless, by choosing varied test tracks (for example, a route through an urban area or a high Alpine road, the “Grossglockner mountain road”) it is, of course, possible to carry out different test runs on different types of roadways which, as any observer will understand, is a complex undertaking and only possible with limitations.
The object of the present invention is, therefore, to describe a method for developing a motor vehicle that has several powered axles and a related test platform allowing for such a vehicle to be developed simply, quickly as well as cost-effectively and independently of a test track.